>>> import numpy as np
>>> np.random.rand(2, 100)    # 生成一个2行100列的数组，元素大小介于0-1之间
array([[0.81964378, 0.04771506, 0.65100483, 0.0066485 , 0.91871471,
        0.15103631, 0.46771212, 0.43113059, 0.05799439, 0.72605262,
        0.78084742, 0.56443492, 0.02568835, 0.13449789, 0.32904806,
        0.82344955, 0.16649785, 0.97543373, 0.59172052, 0.66309511,
        0.51675215, 0.78615406, 0.32624316, 0.87777725, 0.45660334,
        0.87857094, 0.62200539, 0.98008021, 0.22608994, 0.56090398,
        0.35875661, 0.28929522, 0.97120238, 0.92535123, 0.65983975,
        0.84238496, 0.58629816, 0.155536  , 0.79074801, 0.08788872,
        0.21575072, 0.92819647, 0.14736698, 0.18434853, 0.16614201,
        0.6716051 , 0.30115543, 0.87561382, 0.35506054, 0.01613754,
        0.16427282, 0.21325365, 0.25096018, 0.40149182, 0.23253381,
        0.53141691, 0.28953822, 0.87333881, 0.00427381, 0.7417997 ,
        0.50009322, 0.38009854, 0.12716192, 0.91828617, 0.2140139 ,
        0.63639427, 0.26516513, 0.21634017, 0.84756354, 0.27758191,
        0.27632577, 0.86060121, 0.63453095, 0.11719557, 0.66287943,
        0.36554026, 0.62568993, 0.85506066, 0.11499372, 0.05070913,
        0.75731609, 0.67322571, 0.2242588 , 0.05255095, 0.80466241,
        0.92264788, 0.17780867, 0.33334154, 0.57752441, 0.03215144,
        0.00297719, 0.77167313, 0.95677986, 0.4740002 , 0.99857288,
        0.72778312, 0.42450268, 0.09540171, 0.7806744 , 0.91964499],
       [0.75601155, 0.63623498, 0.56764394, 0.23331451, 0.38249758,
        0.03611823, 0.93738241, 0.03998729, 0.29715927, 0.45066693,
        0.22444465, 0.19504426, 0.58078848, 0.98823508, 0.82695651,
        0.21926048, 0.4686177 , 0.98514514, 0.48332013, 0.51023776,
        0.58118674, 0.6078002 , 0.87277555, 0.72588568, 0.30691276,
        0.60798991, 0.04847705, 0.35118891, 0.31312747, 0.05339536,
        0.15690839, 0.72435668, 0.43141231, 0.28045925, 0.46783726,
        0.04601545, 0.2142051 , 0.96453144, 0.52086576, 0.80272952,
        0.48339911, 0.73551129, 0.50866705, 0.58630141, 0.89511003,
        0.67702499, 0.53326297, 0.76126234, 0.17045019, 0.2449404 ,
        0.33925064, 0.27815621, 0.45667023, 0.0338502 , 0.96371712,
        0.02130006, 0.56729768, 0.83126001, 0.23242413, 0.36552882,
        0.62124067, 0.45360203, 0.79962547, 0.37438649, 0.73869832,
        0.40328511, 0.28709422, 0.66419779, 0.23597622, 0.47389357,
        0.45726194, 0.19191252, 0.60556558, 0.73236728, 0.50767956,
        0.49271221, 0.31948233, 0.67100752, 0.55868174, 0.63662819,
        0.65894033, 0.12852269, 0.95724874, 0.79690222, 0.80335603,
        0.53118039, 0.16595452, 0.52253705, 0.4707709 , 0.18363589,
        0.0526909 , 0.02496564, 0.77566785, 0.39572287, 0.97850849,
        0.05721784, 0.91192353, 0.29332641, 0.19101663, 0.96987854]])
        
        
